Contact member for collapsible antenna



Feb. 2, 1960 J. B. CEJKA I 2,923,908

CONTACT MEMBER FOR COLLAPSIBLE ANTENNA Filed Dec. 22, 1954 INVENTOR Jodi 0X .6. 5

ATTO R S United States Patent 9 CONTACT MEMBER FOR ANTENNA Application December 22, 1954, Serial No. 477,063

'3 Claims. (Cl. 339-9) COLLAPSIBLE The present invention relates to contact members for collapsible antennas and more particularly to such members which are well suited for use in collapsible automobile antennas.

It is becoming customary to arrange such antennas so that when collapsed only a few inches of the antenna protrude above the hood or fender cowl mounting, as described in my co-pending application Serial No. 447,992, filed August 5, 1954, now Patent No. 2,840,816, dated June 24, 1958, of which the present application-is a continuation-in-part. To make possible this full retraction of the antenna, the antenna element itself is arranged in a number of telescoping sections. all slide down into the lowest section which also slides down through the mounting when the antenna is retracted. The electrical connection between these antenna sections and the radio in the automobile is generally made by a fixed contact in the mounting which touches the outside of the lowest antenna section and slides along it when the antenna is collapsed or extended.

With prior contact members difiiculties have been experienced in maintaining good electrical contact between the fixed contact and the slidable antenna section. A film of dirt and oil formed on the section, and the prior contacts would fail to wipe it off so that in time the connection was interrupted. This was also likely to occur when the antenna section became twisted to a new position as it was extended.

The contact members described herein as embodying the invention substantially surround the lowest slidable section of the antenna and each includes a conductive sleeve with a plurality of resilient fingers extending axially along the antenna section and adapted to engage the section at a number of places around its circumference.

Among the advantages of this arrangement is that the resilient fingers provide a good wiping action over substantially the entire circumference of the slidable section, insuring good electrical contact regardless of any turning of the antenna.

Another advantage of the contact members described is the fact that each of the resilient fingers is in contact with the antenna section along a substantial portion of its length, providing a plurality of adjacent areas of contact extending axially a significant distance along the antenna section. Advantageously,.the fingers extend upwardly along the antenna section and thus, as it is pulled up, the lower portions of the fingers wipe the section and the tips of the fingers can engage freshly wiped areas.

The contact members described are easily and inexpensively fabricated by mass production and are easy to assemble into the completed antenna. In a preferred commercial form the conductive sleeve and resilient fingers are integrally formed from sheet metal.

The various aspects and advantages of the present invention will be more fully understood from a consider-ation of the following description in conjunction with the accompanying drawing, in which:

The upper sections 2,923,968 Patented Feb. 2, 1960 "ice Figure 1 is a perspective view of a contact member embodying the invention;

Figure 2 is an exploded perspective view'of the contact member of Figure 1;

Figure 3 is a perspective view of a preferred modified form of the contact member;

Figure 4 is an exploded perspective view of the contact member of Figure 3; and

Figure 5 is an axial sectional view showing the contact member and portions of a slidable antenna section and mounting with which it is assembled.

The contact member shown in Figures 1 and 2 includes, generally, an annular insulator 10 and a contact assembly 12 with a sleeve 14 which fits within the axial opening 16 of the insulator. To hold the contact assembly in the insulator, the sleeve 14 has a flange 18 at one end which abuts against a shoulder in the insulator 10 adjacent one end of the opening 16 when the contact assembly is slid into the opening 16 during assembly. The other end of the sleeve 14 is rolled over after assembly to form a lip 20 against a similar shoulder 22 adjacent the other end of the opening 16.

Projecting from the inside of the flanged end of the sleeve 14 are three resilient contact fingers 24. These fingers are arcuate in cross section with their inner ends spot Welded to the inside of the sleeve 14 at three equally spaced points 26 before the sleeve 14 is slid into the insulator. The free ends of the contact fingers converge slightly so as to exert pressure on the antenna section when it is slid through the sleeve portion 14.

The external connection from the contact assembly 12 to the automobile radio is made through a pin 28 which projects radially through a hole 30 in a circular boss 32 on the outside wall of the insulator 10. The inner end of the pin 28 is threaded into a small square nut 34 which is fastened to the outside of the sleeve 14 at a mid-point aligned with the inner end of one of the fingers 24. An axial recess 36 in the wall of the opening 16 behind the boss 32 provides clearance for the nut 26 when the contact assembly is slid into the hole 16.

The outer wall of the insulator 10 is cylindrical and is arranged to fit snugly Within a tubular portion 38 (as shown in Figure 5) of the antenna mounting with the boss 32 fitting into a threaded nipple 40 on the base 41 of the mounting. This nipple is adapted to hold the sleeve of a coaxial cable coupling (not shown) When the inner conductor of the coaxial cable is connected with the pin 28. A pair of semi-circular axial recesses 42 at each side in the outer wall of the insulator provide clearance for a rolled seam in one side of the tube 38 and enable the contact member to be assembled in the antenna mounting with the fingers 24 either up or down. These recesses 42 also increase the resilience of the insulator 10 when the sleeve 14 is slid into place.

From the inner shoulders 22 at each end of the hole 16, the insulator 10 flares out at about a 30 angle to its axis toward each end. The insulator, has an overall length about twice the length of the opening 16 so as to seat firmly in the tubular portion 38 of the antenna mounting and has a groove 44 around its outside at each end to facilitate assembly.

The commercial form of the contact member shown in Figures 3, 4 and 5 is generally similar to the contact member described above, and parts performing corresponding functions have corresponding reference numbers followed by the sufiix a.

In this contact member, the contact assembly 12a is punched and rolled from a sheet of brass to form a sleeve portion 14a with three resilient fingers 24a projecting from one end. These fingers 24a are defined by the spaced seam 45 and by two axial slots 46 stamped in the blank before it is rolled up.

To engage one h shoulde s a he nsula r 1 a, three semi-circular cars 48 are knocked out perpendicular to the sleeve portion 14a, each axially aligned with one of the fingers 24a, At the otheu end of. the, sleeve portion 14a are three square tabs 50 which;are -bent over onto: the other shoulder 22a after the sleeve portion 14a is slid into the insulator 10a. Thus the contact assembly 12aris-held against movement axially o f the insulator 10a.

Among the advantages of this contact member" is the fact the pin 28:; can be fastened to the sleeve 14a before the contact assembly 12a is slid. into-the insulator 100. To hold the inner end of the pin 28a. which is reducedin diameter to form a shoulder 51a bump 52with-a1hole 53 therein is formed in the sleeve portion 14a; in. line with one of the slots 46 The reduced, end of the pin 28a fits through thishole ,3 and is held in place bybeingpeened over with a punch insertedthrough a; b01654 in the' sleeve portion 14a-opposite to the hole 53. The bump 52. provides clearance between the inner peenc'd end of. the pin 28a and the slidableantc-nna section 56. (figure 5 which slides through the contact member.

To enable the contact assembly 12a; and pin 28a to be slid into the insulator a, a radial slot 58, is out between a V-notch 60 at one end of the insulator and the hole 30a. The insulator 10a is of black polystyrene and; is sulficiently flexible so that the pin 28:; can he pushed along the slot 5? into the hole 36M.

In a particular commercial form, the insulator 10a is about inch long and about inch in diameter. The opening 16a is about inch long andabout inch in diameter. The boss 32a is about inch long and 6 inch in diameter. The blank forming thcsleeve portion 14a and fingers 24ahas an axiallength-of 1%,inches with the fingers 24a about /2 inch long and about A: inch wide.

The two slots 46 are about- A2 inch wide, with the fingers.

24a being bent in slightly so as to grip resiliently the outside of the slidable antenna section 56.

From the foregoing description it will be seen that I have provided contact members well suited to'attain the ends and objects hereinbefore set forth, and it will be understood that the scope of my inventioniincludes various alternatives and modifications which may be made in adapting the contact members for usein each particular application,

I claim:

1. In a collapsible antenna of thetype having; a: tubular base and an antenna section slidable therein, a contact member for slidably supporting said slidable section in insulated relation to said base and for electrically connecting said slidable section to an external circuit; said contact member comprising a generally annular. insulator fixed in said base and having an axial opening therethrough, a cylindrical boss on one side of said insulator with a radial opening extending out from said axial opening through said boss, a conductive sleeve portion fitting within said axial opening, resilient fingers projecting axially from said sleeve portion with their free ends converging slightly toward one another, and a contact pin projecting from said conductive sleeve through said radial opening, and a nipple projecting radially from said base, said nipple having a circular opening therethrough into which said boss is received to lock said insulator against movement longitudinally of said base.

2. In a collapsible antenna of the type having a tubular base and an antenna section slidable therein, a contact member for slidably supporting said slidable section in insulated relation to said base and for electrically con necting said slidable section to an external circuit, said contact member comprising a generally annular insulator fixed in said base and having an axial opening therethrough, abutments in said insulator adjacent each end of said opening, said insulator having a cylindrical boss extending radially from one side and a radial opening extending concentrically; through said boss from said axial opening to the outside of said insulator, a slot extending through said insulator from the axial opening to the outside and from one end of said insulator to said radial opening, said insulator having a recessin the wall of said axial opening aligned with said slot, a conductive sleeve portion fitting within said axial opening, projecting flange portions-on said; sleeve portion resting against said abutments, a plurality of resilient contact fingers projecting axially from-one end ofsaid sleeve portion with the free ends of said fingers converging slightly toward one another, and a contact pin projecting radially from said sleeve portion through the radial opening in said insulator, and a nipple projecting radially from said base, said nipple having a circular opening therethrough into which said boss is received to lock said insulator against movement longitudinally of said base.

3. In a collapsible antenna of the type having a tubular base and an antenna section slidable therein, a contact member for slidably supporting said slidable section in insulated relation to said base and for electrically connecting said slidable section to an external circuit, said contact member comprising a, generally annular insulator fixed in said base and having an axial opening extending from one end to the other and a cylindrical boss extending radially from one side with a radial opening extending coaxially through said boss and intersecting saidaxial opening, and' a sleeve portion rolled from sheet material with anopenseam along one side, a plurality of resilient fingers integral with said sleeve portion and projecting axially from one of the ends of said sleeve portion, said fingers being defined by said seam and at least one slot in said sheet material extending. axially from said end, a

flange element cut from said sheet material andturned outwardly from the axis of said sleeve portion to engage said insulator, and a bump in said sleeve portion having a hole therein, a contact pin projecting radially out from the hole in saidsleeve portion, the inner end of said pin being peenedover- 'inside of said hole, said sleeve portion havinga secondhole in the side opposite from and aligned withsaid firsthole, and; a nipple projecting radiallyfrom said base, said nipple having a circular opening therethroughinto which said boss is-received to lock said insulator against movement longitudinally of said base.

References Cited in the-file of this patent UNITED STATES PATENTS 2,204,525 Bolser- June 11, 1940 2,450,467 Clark Oct. 5, 1948 2,463,826 Thacker Mar. 8, 1949 2,632,106 Carlson Mar. 17, 1953 2,754,487 Carr et a1. July 10, 1956- 

